Push button operated circuit interrupter



June 21, 1949. L, PlERCE 2,473,901

PUSH suwwon OPERATED cmcum INTERRUPTER Filed July 31, 194'? g! wnuzssss; A mvsmon L awrence P/erce,

4 f iwa 5M ATTORNEY Patented June. 21, 1949" PUSH BUTTON OPERATED CIRCUIT INTERRUPTER Lawrence Pierce, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 31, 1947, Serial No. 765,105

8 Claims. (cl. 200-416) This invention relates to circ'uitinterrupters and more particularly to circuit breakers of the push-button operated type.

An object of the invention is to provide a circuit breaker embodying an improved manual operating mechanism.

Another object of the invention is to provide a circuit breaker having a snap acting operating mechanism with an improved manual operating means.

Another object of the invention is to provide a circuit breaker having an operating mechanism comprising an overcenter spring with an improved push-button manual operating mechanism.

The novel features that are considered characteristic of the invention are set forth in particular in the appendedclaims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will best be understood from the following description thereof when read in connection with the accompanying drawing, of which:

Fig. 1 is a vertical sectional view of the circuit breaker showing the operating mechanism and contact means in the closed position;

Fig. 2 is a fragmentary vertical sectional view showing the operating mechanism in the manually open position;

Fig. 3 is a fragmentary view similar to Fig. 2 but showing the operating mechanism in the tripped open position; and,

Fig. 4 is a fragmentary view partly in section, illustrating the current responsive trip device and a portion of the latching means of the breaker.

Referring to the drawing, the circuit breaker comprises a base 9 of sheet metal construction provided with a U-shaped frame II for supporting the circuit breaker unit. The base 9 and the circuit breaker unit are mounted in an enclosure comprising a casing l3 and a cooperating cover prises a plurality of sets of spaced stationary contacts 23 (only one set being shown) and a plurality of movable bridging contact members 25 (only one being shown), which serve to bridge the stationary contacts 23 in the closed position of the breaker. The conducting bridging contact member carries a pair of movable contacts 21 which cooperate with the stationary contacts 23 to open and close the circuit.

The stationary contacts 23 are mounted on the opposed ends of a pair of conducting strips 29 and 3| supported on an insulating block 33, suitably mounted on the base 9. The upper conducting strip 29 is formed at right angles and is provided with a terminal screw for connecting the contact in an electrical circuit.

The bridging contact member 25 which carries the movable contacts 21 is mounted in a frame 31 and is biased by means of a spring 39 compressed between the back of the contact member 25 and the frame 31.

The frame 31 which supports the bridging member 25 is mounted on a cross-bar ll of insulating material which is secured to the movable switch operating member I! and extends across the device, and carries in like manner the bridging contact members for the other poles (not shown). The switch member I! is channel-shaped and the sides thereof are provided with slots 43 which engage a roller 45 mounted on a fixed rod 41 extending between and supported in the side members of the U-shaped frame H to movably support the switch member.

The operating mechanism [9 comprises, in general, a releasable carrier 49 which is pivotally mounted by means of a pivot pin 5| supported in the side members of the main frame, a pair of actuating links 53 pivotally connected at their upper ends by a pivot pin 55 to the carrier 49 and pivotally connected at their lower ends by means of a pivot pin 51 to the movable switch member IT. A pair of over-center springs 59 (only one being shown) are disposed on opposite sides of the carrier 49 and the links 53. The lower ends of the. over-center springs 59 are connected to the pivot pin 51 which connects the' links 53 to the switch member l1 and the upper ends of the springs 59 are connected to a rod 6| movably supported in slots 63 in the side walls 65 (only one being shown) of a channel shaped rocker 61. The lower edges of the side walls 65 of the rocker are provided with aligned V-shaped notches 69 which engage formed over ears H on the side members of the main frame to pivotally support the rocker 61. Disposed one on each side.

of the pivot 1| for the rocker 51 is a pair of push buttons 18 and 15 which are slidably mounted in suitable openings in the cover i5 and having their inner ends rounded for cooperation with the rocker 51.

The carrier 48 is releasably held in a normally latched position, as shown in Figs. 1 and 2, by means of a latch 11 which is pivotally mounted on a pivot pin 18 extending transversely between the side members of the frame II. The free end of the carrier 48 is provided with a latch nose 8| which engages under the-edge of an opening 88 in the latch member I1. The latch member 11 is releasably restrained in latching position by means of a second latch member 85 which is pivotally mounted on a pivot pin 81 extending between and supported by the side members of the frame II. The latch member 85 is biased in latching direction about its pivot by means of a compression spring 88. The lower end of the latch member 11 normally abuts against the free end of the second latch member 85 so that the latch member 85 normally prevents releasing movement of the main latch 11.

With the parts in the closed position shown in Fig. 1, and it is desired to manually open the circuit, the push button I8 is pressed inwardly as far as it will go, .ius rotating the rocker 51 in a counterclockwise direction from its Fig. 1 position to the position in which it is shown in Fig. 2. During the movement of the rocker 51, the rod 5| will be moved to the opposite end of the slot 53 by the force exerted by the springs 58 and thus carry the line of action of the springs 58 across to the left of the pivot 55 to effect movement of the actuating links 53 and the switch member l1, together with the movable bridging contact member 25 carried thereby, to the open circuit position with a snap action. If the overcenter springs 59 were attached to the rocker 55 at its point of greatest overcenter movement, due to the limited movement of the rocker the springs would not be moved overcenter across the line 555'| far enough to overcome the frictional forces and operate the switch members. By the provision of the slot 83 and the rod 5| to which the outer ends of the springs are attached, the ends of the springs associated with the rocker 55 are caused to move overcenter relative to the operator a greater distance than the overcenter movement of the operator or rocker. The movement of the switch member ll to the manually open circuit position is limited by engagement of the right hand end of the slot 43 therein with the roller 45 as shown in Fig. 2.

In order to manually close the circuit breaker, the closing push button 15 is depressed rotating the rocker 51 in a clockwise direction from the position shown in Fig. 2, to the position in which it appears in Fig. 1. During this movement of the rocker 51 the roller 8| moves back to its original position carrying the line of action of the over-center springs 58 .across to the right of the pivot 55 to effect movement of the actuating links 53 and the switch member H to the closed circuit position as shown in Fig. 1. The roller 45 permits the switch operating member I! to be rolled freely to open and closed positions, and also serves to guide the switch member so that it is moved substantially in a straight line during manual switching operations.

The trip device is of the type disclosed in U. S. Patent No. 2,265,004, issued December 2, 1941, to Lawrence Pierce and Stephan Miller and assigned to the assignee of the present invention, for

4 which reason only a brief description thereof will be given herein.

The trip device comprises a plurality of current responsive devices 8| (Fig. 4) there being a .current responsive device 8| associated with at least two poles of the breaker. Each of the current responsive devices 8| (only one being shown in detail) comprises a snap-acting bimetallic disc 83, a heater coil 85, a supporting cylinder 81 mounted in an insulating block 88 secured to the frame ii, an insulating button it! and a trip member I55 for engaging and operating the latch member 85. The bimetallic disc 88 is of the type which, when heated a predetermined amount in response to overload currents, snaps suddenly from one position to another and, when cooled below a predetermined temperature, snaps back to its original position.

When the bimetal disc 88 is heated a predetermined amount in response to overload currents and snaps from the position in Fig. 4, the trip member I03 engages the latch member and operates it to the position shown in Fig. 3, thus effecting release of the main latch 11 which is actuated to releasing position under the influence of the overcenter springs 58 to effect release of the carrier 48. When the carrier 48 is released, it is moved in a clockwise direction by the force dxerted by the over-center springs 58. This clockwise movement of the pivoted carrier 48 carries the pivot pin 55 to the right across the line of action of the over-center springs 58 to the position shown in Fig. 3. As soon as the pivot pin 55 crosses to the right of the line of action of the over-center springs, these springs act to move the switch operating member I! to a tripped open position. The switch member I"! in moving to its tripped open position pivots in a clockwise direction about the roller 45 and is then moved by the force exerted by the over-center springs 58 to the open circuit position, as shown in Fig. 3.

Before the circuit breaker can be reclosed following an automatic opening operation, it is necessary to reset the carrier 48 and the latches I1 and 85 to their latching positions. In order to reset the mechanism, the push button 13 is depressed to the limit of its movement, thus rocking the rocker 51 in a counterclockwise direction from its Fig. 3 position to its Fig. 2 position. During this counterclockwise movement of the rocker 51, a cam portion I55 thereof engages a projection iill' on the carrier 49 and moves the carrier 48 counterclockwise to the position shown in Fig. 2. The counterclockwise movement 01. the carrier 48 causes the latch nose 8| to engage the lower edge of the opening 83 of the latch member 11 and move that member to its latching position. At this time the bimetal element 83 has cooled and snapped to its Fig. 4 position withdrawing the trip member I53 and releasing the latch member 85. When the latch member 11 has been restored to its latching position, the second latch member 85 is moved by the spring 88 to its latching position wherein its end reengages the end of the latch member 11. The mec anism is now completely reset and the circui t reaker can be reclosed by depressing the "on button 15 to close the circuit breaker in the previously described manner.

From the foregoing description, it will be apparent that there is provided an improved automatic circuit breaker operating mechanism wherein one end of an over-center spring is controlled by a push button operated rocking member to move the spring over center for the purpose of operating the breaker to open and pic a greater distance over center than it would if the spring were secured to the rocking member.

While the invention has been disclosed in ac-' cordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details thereof may be made without departing from some of the essential features of'the invention.

I claim as my invention:

1. In a circuit breaker having a movable switch operating member, the combination of an operating mechanism for moving said switch operating member to open and to closed circuit positions comprising a pivoted operator, an over-center spring having one and associated with said switch operating member, a spring support member supporting the other end of said over-center spring on said operator for movement relative to said operator, manual means for moving said pivoted'operator, said pivoted operator having a slot therein for permitting the end of said over-center spring related to said pivoted operator to move overcenter a greater distance than the over-center movement of'said pivoted operator to effect operation of said pivoted member, means releasable to eiIect automatic movement of said switch operating member to open position, and means on said pivoted operator for resetting said releasablemeans upon opening movement of said generator.

2. In a circuit breaker having a movable switch operating member, the combination of an oper*- ating mechanism for moving said switch operating member to open and closed circuit positions comprising an over-center spring, an operator movable to two positions to eiIect over-center movement of said spring to thereby move said switch operating member to said open and closed circuit positions, manually operable means for moving said operator to said two positions, a sprin support member mounting one end of said over-center spring on said operator and movable relative to said operator upon movement of said 6 [r operating member movable to open and positions toopen and close said circuit, the combination of an operating mechanism for moving said switch operating member to said open and closed positions comprising a pivoted operator having a slot therein and movable to an open and to a closed position, a member engaging said slot for movement therein relative to said operator, an over-center spring connecting said switch operating member and said member, manually operable means comprising a pair of push buttons disposed one on each side of the pivot of said operator and operable to effect movement of said operator to said open and closed positions, said member upon movement of said operator to either of its positions moving within said slot relative to said actuator to effect over-center movement of said spring to thereby actuate said switch operating member, a member releasable to eifeet automatic movement of said switch member to open position, a trip device operable in response to over-load currents to release said releasable member, and means on said operator for resetting said releasable member;

5. In a circuit breaker having a movable switch operating member, the combination of an operating mechanism for moving said switch operating member to open and to closed circuit positions comprising a pivoted operator having a longitudinal slot therein, an over-center spring having one end associated with said switch operating member, a member disposed in said slot forsupporting the other end or said over-center spring on said operator for movement relative to said operator to either one of said two positions to effeet over-center movement of said spring, a releasable member operable when released to effect automatic movement of said switch operating member to open position, and means on said operator for engaging and resetting said releasable .member upon'opening movement of said operator.

3. In a circuit breaker comprising a switch operating member movable to open and closed positions to open and close said circuit, the combination of an operating mechanism for moving said switch operating member to said open and closed positions comprising an over-center spring having one end pivotauy connected to said switch operating member, an operator having a slot therein, a spring support member engaging said slot for movement relative to said operator upon movement of said operator, the other end of said over-center spring being attached to and movable with said spring support member, manual means for actuating said operator to cause movement of said spring support member relative to said operator whereby the end of the over-center spring attached to said spring support member is moved over-center a greater distance than it would if attached directly to said operator, and a member releasable to efiect movement of said switch operating member to open position irrespective of the closed position of said operator.

4. In a circuit breaker comprising a, switch operator, manual means for moving said operator, and said operator having a longitudinal slot therein for permitting the end of said over-center spring related to said operator to move a greater distance than themovement of said operator to effect over-center movement of said spring, and means releasable to efiect movement of said switch operating member to open position irrespective of the closed position of said operator.

6. In a circuit breaker having a movable switch operating member, the combination of an operating mechanism for moving said switch operating member to open and to closed circuit positions comprising a pivoted operator, an over-center spring having one end associated with said switch operating member, a support member supporting the other end of said over-center spring on said operator for movement relative to said operator, manual means for moving said operator, said operator having a longitudinal slot therein for permitting the end of said over-center spring supported by said operator to move a greater distance than the movement of said operator to effect over-center movement of said spring, means releasable to effect movement of said switch operating member to open position irrespective of the closed position of said operator, and means on said operator for engaging and resetting said releasable means upon opening movement of sai operator.

'I. In a circuit breaker comprising a movable switch operating member, the combination of an operating mechanism for moving said switch operating member to open and closed positions comprising a releasable member, means operatively connecting said switch operating member to said releasable member, an operator movable between thereto upon movement of said operator to either of its positions, an over-center spring connected between said member and said switch operating member, manual means for moving said operator to its first and second positions to eflect overcenter movement of said spring, said member upon movement or said operator to either of its positions moving relative thereto a distance greater than the movement of said operator, and trip means operable to release said releasable members to effect opening movement of said switch operating member.

8. In a circuit breaker comprising a movable switch operating member, the combination of an operating mechanism for moving said switch operating member to open and closed positions comprising a releasable member, means operatively connecting said switch operating member to said releasable member, an operator movable between a first and a second position to move said switch operating member to said open and closed posi 20 REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,265,004 Pierce et a1. Dec. 2, 1941 2,388,617 Link Nov. 6, 1945 2,430,138 Parker Nov. 4, 1947 

